1. Field of the Invention
The present invention relates to welding equipment, and more particularly pertains to a new and improved welding shield which is provided with ventilation means.
2. Description of the Prior Art
The use of various ventilation devices for welding shields is well known in the prior art. All of these devices are directed to providing a flow of air around a welding hood or shield, and the prior art is replete with patented devices that accomplish the desired function.
A number of these prior art devices are directed to the providing of a tubular member around a welder's head, with such tubular member having a plurality of apertures through which a flow of ventilating air is directed. For example, U.S. Pat. Nos. 3,921,223 which issued to D. Hoyecki on Nov. 25, 1975 and 4,195,363 which issued to B. Jenson on Apr. 1, 1980 both disclose these type of devices. While being operable to provide a desired flow of ventilating air and to keep fumes and other noxious gasses away from the welder's face, it can be appreciated that neither of these devices are particularly adapted to maintain a clear viewing shield.
There are, however, patented ventilation devices which do provide for a flow of air over a viewing shield. For example, U.S. Pat. No. 3,922,722, which issued to Pokhodnya et al on Dec. 2, 1975, discloses the positioning of a perforated pipe on the outside of a helmet just under the light filtering viewing lens. A flow of air is directed to the pipe from an attached conduit, and the air passing outwardly through the perforations in the pipe passes over the viewing lens so as to keep an exterior surface thereof free from accumulated dust and other debris. At the same time, a flow of fresh air in front of the helmet reduces the amount of noxious fumes inhaled by the welder. While being operable to perform its intended function, it can be appreciated that condensation from the welder's breath will still condense on an interior surface of the viewing lens which could then result in substantial visibility problems.
By the same token, U.S. Pat. No. 4,309,774, which issued to C. Guzowski on Jan. 12, 1982, discloses a ventilated helmet wherein an electrically operated fan is adapted to move air to an interior portion thereof. The fan is operated through the use of a light sensitive, electrical energy producing cell, and the flow of air is designed to prevent the accumulation of gaseous fumes within the helmet during a welding operation. The invention disclosed in this patent is not designed to provide for a flow of air across an exterior surface of the viewing lens, nor is the air flow within the shield directed in a manner which would allow it to pass across the viewing lens so as to prevent condensation from forming thereon.
While all of these prior art devices are substantially similar in design and function, there would appear to be a continuing need for minor improvements which are of a patentable nature due to the crowded status of the art. Inasmuch as no single prior art patent discloses a means of providing ventilating air which would also keep a viewing lens free of dust accumulation and condensation, there would appear to be a continuing need for ventilation designs which would perform this desired function. In this respect, the present invention addresses this need.